In the current phase of this research program we are placing the most effort into using the 14C-2-Deoxy-Glucose technique to explore the functional changes in the central nervous system associated with peripheral and central thermal stimulation and the events of hibernation. Golden mantled ground squirrels are chronically prepared with hypothalamic thermodes as well as jugular catheters. During an experiment the animal is injected through the catheter with a small quantity of 14C-2DG while an event of interest such as hypothalamic cooling, entrance into hibernation, and arousal from hibernation is on going. After a period of incubation the animal is sacrificed and its brain is frozen and sectioned. The sections are autoradiographed and the optical densities of the autoradiographic images of neural structures are taken as measures of the glucose utilization of these structures during the period of incubation. Comparisons with euthermic controls under thermoneutral conditions without hypothalamic stimulation provide a measure of the changes in activity of specific neural structures associated with differences of thermoregulatory activities, states of arousal, and events of hibernation.